diff --git a/lib/windows/AutoOS.ClaudeAutostart.psm1 b/lib/windows/AutoOS.ClaudeAutostart.psm1
index 98c4a9f..551ad66 100644
--- a/lib/windows/AutoOS.ClaudeAutostart.psm1
+++ b/lib/windows/AutoOS.ClaudeAutostart.psm1
@@ -43,7 +43,7 @@ function Get-AutoOSClaudeDefaults {
                 foreach ($p in $block.PSObject.Properties) { $table[$p.Name] = $p.Value }
                 if ($table.Count -gt 0) { return $table }
             }
-        } catch { }
+        } catch { Write-Verbose $_.Exception.Message }
     }
     @{
         enabled = $true; snapshot_interval_mins = 5; liveness_window_mins = 240
@@ -272,7 +272,7 @@ function Get-AutoOSClaudeState {
                     sessions        = @($doc.sessions)
                 }
             }
-        } catch { }
+        } catch { Write-Verbose $_.Exception.Message }
     }
     [pscustomobject]@{ version = $script:StateVersion; captured_at = 0; captured_at_iso = $null; sessions = @() }
 }
diff --git a/lib/windows/AutoOS.Detect.psm1 b/lib/windows/AutoOS.Detect.psm1
index b1934ec..a6dccd8 100644
--- a/lib/windows/AutoOS.Detect.psm1
+++ b/lib/windows/AutoOS.Detect.psm1
@@ -40,20 +40,24 @@ function Get-AutoOSShimDirectory {
         not necessarily written itself there, and a per-user shim directory is
         only on PATH for the user who ran the installer.
     #>
-    $home_ = $env:USERPROFILE
+    $home_ = if ($env:USERPROFILE) { $env:USERPROFILE } else { $env:HOME }
+    $progData = if ($env:ProgramData) { $env:ProgramData } else { 'C:\ProgramData' }
+    $localApp = if ($env:LOCALAPPDATA) { $env:LOCALAPPDATA } else { $(Join-Path $home_ 'AppData\Local') }
+    $progFiles = if ($env:ProgramFiles) { $env:ProgramFiles } else { 'C:\Program Files' }
+    $appData = if ($env:APPDATA) { $env:APPDATA } else { $(Join-Path $home_ 'AppData\Roaming') }
     @(
         # Scoop: user-scope by default, global when SCOOP_GLOBAL is set.
         (Join-Path $home_ 'scoop\shims'),
         $(if ($env:SCOOP) { Join-Path $env:SCOOP 'shims' }),
         $(if ($env:SCOOP_GLOBAL) { Join-Path $env:SCOOP_GLOBAL 'shims' }),
-        (Join-Path $env:ProgramData 'scoop\shims'),
+        (Join-Path $progData 'scoop\shims'),
         # Chocolatey.
-        (Join-Path $env:ProgramData 'chocolatey\bin'),
+        (Join-Path $progData 'chocolatey\bin'),
         # winget's own shim directory for portable packages.
-        (Join-Path $env:LOCALAPPDATA 'Microsoft\WinGet\Links'),
-        (Join-Path $env:ProgramFiles 'WinGet\Links'),
+        (Join-Path $localApp 'Microsoft\WinGet\Links'),
+        (Join-Path $progFiles 'WinGet\Links'),
         # npm -g, pipx/uv and cargo all install here and all rely on PATH.
-        (Join-Path $env:APPDATA 'npm'),
+        (Join-Path $appData 'npm'),
         (Join-Path $home_ '.local\bin'),
         (Join-Path $home_ '.cargo\bin'),
         (Join-Path $home_ 'bin')
@@ -122,7 +126,7 @@ function Get-AutoOSWingetPackageProcess {
         $process = [Diagnostics.Process]::Start($psi)
         # Close stdin so a prompt that slipped past --disable-interactivity reads
         # EOF and gives up, instead of sitting there until the timeout.
-        try { $process.StandardInput.Close() } catch { }
+        try { $process.StandardInput.Close() } catch { Write-Verbose $_.Exception.Message }
         $process
     } catch { $null }
 }
@@ -144,7 +148,7 @@ function Get-AutoOSWingetPackageResult {
             $Process.Kill()
         }
     } catch { $packages = @() }
-    finally { try { $Process.Dispose() } catch { } }
+    finally { try { $Process.Dispose() } catch { Write-Verbose $_.Exception.Message } }
     $packages
 }
 
diff --git a/lib/windows/AutoOS.Serve.psm1 b/lib/windows/AutoOS.Serve.psm1
index f732bf6..6c7420e 100644
--- a/lib/windows/AutoOS.Serve.psm1
+++ b/lib/windows/AutoOS.Serve.psm1
@@ -266,7 +266,7 @@ function Get-AutoOSExampleBlock {
     try {
         $block = (Get-Content -LiteralPath $path -Raw -Encoding UTF8 | ConvertFrom-Json).$Name
         if ($block) { return $block }
-    } catch { }
+    } catch { Write-Verbose $_.Exception.Message }
     @{}
 }
 
@@ -286,7 +286,7 @@ function Get-AutoOSDetectedAnswers {
         try {
             $value = (& git config --global $pair.Setting 2>$null | Select-Object -First 1)
             if ($value) { $answers[$pair.Key] = [string]$value }
-        } catch { }
+        } catch { Write-Verbose $_.Exception.Message }
     }
     $answers
 }
diff --git a/tests/run-tests.ps1 b/tests/run-tests.ps1
index fab45f6..114a3e3 100644
--- a/tests/run-tests.ps1
+++ b/tests/run-tests.ps1
@@ -303,13 +303,25 @@ Test-Case 'a different product sharing a prefix is never matched' {
 }
 
 Test-Case 'the shim directories package managers use are probed even when PATH is stale' {
-    $dirs = @(Get-AutoOSShimDirectory)
-    foreach ($want in @('scoop\shims', 'chocolatey\bin', 'Microsoft\WinGet\Links')) {
-        if (-not @($dirs | Where-Object { $_ -like "*$want*" })) {
-            throw "no probe directory for $want in: $($dirs -join '; ')"
+    $env_USERPROFILE_backup = $env:USERPROFILE
+    $env_ProgramData_backup = $env:ProgramData
+    $env_LOCALAPPDATA_backup = $env:LOCALAPPDATA
+    $env:USERPROFILE = if ($env:USERPROFILE) { $env:USERPROFILE } else { 'C:\Users\runneradmin' }
+    $env:ProgramData = if ($env:ProgramData) { $env:ProgramData } else { 'C:\ProgramData' }
+    $env:LOCALAPPDATA = if ($env:LOCALAPPDATA) { $env:LOCALAPPDATA } else { 'C:\Users\runneradmin\AppData\Local' }
+    try {
+        $dirs = @(Get-AutoOSShimDirectory)
+        foreach ($want in @('scoop\shims', 'chocolatey\bin', 'Microsoft\WinGet\Links')) {
+            if (-not @($dirs | Where-Object { $_ -like "*$want*" })) {
+                throw "no probe directory for $want in: $($dirs -join '; ')"
+            }
         }
+        Pass
+    } finally {
+        $env:USERPROFILE = $env_USERPROFILE_backup
+        $env:ProgramData = $env_ProgramData_backup
+        $env:LOCALAPPDATA = $env_LOCALAPPDATA_backup
     }
-    Pass
 }
 
 Test-Case 'a shim directory off the persistent PATH still resolves a verify command' {
diff --git a/tests/run-tests.sh b/tests/run-tests.sh
index 7e759a8..f3fbb70 100644
--- a/tests/run-tests.sh
+++ b/tests/run-tests.sh
@@ -905,6 +905,50 @@ if it "the payload carries the platform list"; then
     grep -q "component_platforms" lib/linux/serve.py && pass || fail "serve.py does not compute platforms"
 fi
 
+if it "component_platforms computes cross-platform availability correctly"; then
+    if python3 - <<'PY'
+import sys, os, pathlib, json, tempfile
+sys.path.insert(0, './lib/linux')
+
+with tempfile.TemporaryDirectory() as tmpdir:
+    import serve
+    serve.ROOT = pathlib.Path(tmpdir)
+    cat_dir = serve.ROOT / "catalog"
+    cat_dir.mkdir()
+
+    # Create fake catalogs
+    windows = {"categories": [{"components": [{"id": "c1"}, {"id": "c2"}]}]}
+    linux = {"categories": [{"components": [{"id": "c2"}, {"id": "c3"}]}]}
+    macos = {"categories": [{"components": [{"id": "c1"}, {"id": "c3"}]}]}
+
+    (cat_dir / "windows.json").write_text(json.dumps(windows), encoding="utf-8")
+    (cat_dir / "linux.json").write_text(json.dumps(linux), encoding="utf-8")
+    (cat_dir / "macos.json").write_text(json.dumps(macos), encoding="utf-8")
+
+    sys.argv = ["serve.py"]
+
+    serve._PLATFORMS_CACHE = None
+    res = serve.component_platforms()
+
+    if sorted(res.keys()) != ["c1", "c2", "c3"]:
+        print("keys wrong:", res, file=sys.stderr)
+        sys.exit(1)
+
+    if sorted(res["c1"]) != sorted(["macos", "windows"]):
+        print("c1 wrong:", res["c1"], file=sys.stderr)
+        sys.exit(1)
+
+    if sorted(res["c2"]) != sorted(["linux", "windows"]):
+        print("c2 wrong:", res["c2"], file=sys.stderr)
+        sys.exit(1)
+
+    if sorted(res["c3"]) != sorted(["linux", "macos"]):
+        print("c3 wrong:", res["c3"], file=sys.stderr)
+        sys.exit(1)
+PY
+    then pass; else fail "component_platforms returned incorrect mappings"; fi
+fi
+
 if it "Handy is offered on every platform"; then
     n="$(grep -l '"id": "handy"' catalog/*.json | wc -l)"
     assert_eq "$n" "3"